1 /* 2 * Copyright 2017, OpenCensus Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package io.opencensus.common; 18 19 import java.math.BigInteger; 20 21 /** Util class for {@link Timestamp} and {@link Duration}. */ 22 final class TimeUtils { 23 static final long MAX_SECONDS = 315576000000L; 24 static final int MAX_NANOS = 999999999; 25 static final long MILLIS_PER_SECOND = 1000L; 26 static final long NANOS_PER_MILLI = 1000 * 1000; 27 static final long NANOS_PER_SECOND = NANOS_PER_MILLI * MILLIS_PER_SECOND; 28 TimeUtils()29 private TimeUtils() {} 30 31 /** 32 * Compares two longs. This functionality is provided by {@code Long.compare(long, long)} in Java 33 * 7. 34 */ compareLongs(long x, long y)35 static int compareLongs(long x, long y) { 36 if (x < y) { 37 return -1; 38 } else if (x == y) { 39 return 0; 40 } else { 41 return 1; 42 } 43 } 44 45 private static final BigInteger MAX_LONG_VALUE = BigInteger.valueOf(Long.MAX_VALUE); 46 private static final BigInteger MIN_LONG_VALUE = BigInteger.valueOf(Long.MIN_VALUE); 47 48 /** 49 * Adds two longs and throws an {@link ArithmeticException} if the result overflows. This 50 * functionality is provided by {@code Math.addExact(long, long)} in Java 8. 51 */ checkedAdd(long x, long y)52 static long checkedAdd(long x, long y) { 53 BigInteger sum = BigInteger.valueOf(x).add(BigInteger.valueOf(y)); 54 if (sum.compareTo(MAX_LONG_VALUE) > 0 || sum.compareTo(MIN_LONG_VALUE) < 0) { 55 throw new ArithmeticException("Long sum overflow: x=" + x + ", y=" + y); 56 } 57 return x + y; 58 } 59 } 60